JPH03224664A - Coating finishing method - Google Patents

Abstract

PURPOSE:To obtain a coated film which is free from peeling, etc., and has excellent finish appearance by using a coating material of a specified compsn. as a colored coating material at the time of coating a porous blank material with the colored material and UV curing type clear coating material. CONSTITUTION:The porous blank material, such as plaster board, which is of a flat plate shape and has a porous surface. The porous blank material is coated with the colored coating material subjected to viscosity adjustment by a method, such as spray coating. The colored material to be used consists essentially of a phenoxy resin, urea resin and acid catalyst having 5000 to 20000 number average mol.wt. and 10000 to 100000 weight average mol.wt. and consists of an org. solvent contg. a lower alcohol. After the colored material is dried, the blank material is coated with the UV type clear coating material by a reverse roll coater or knife coater. Further, the clear coated film is cured by irradiation with UV rays. The coated film having the excellent interlayer adhesiveness between the colored coated film and the clear coated film and the excellent finish appearance is obtd. in this way.

Description

[Detailed Description of the Invention] l! FIELD OF THE INVENTION The present invention relates to a method of coating a porous material such as a wood base material with a colored paint, and then applying an ultraviolet curable paint with a roll coater or a knife coater.

1 and 8; As a method for continuously and quickly coating porous materials, a colored paint is applied, and then an ultraviolet curable clear paint is applied to the painted surface using a reverse roll coater, knife coater, etc. There are many methods of painting that fill the porous parts of the paint.

In this painting method, after applying the colored paint, the clear paint is immediately applied using a reverse roll coater, etc., so the colored paint has a hardening property that quickly forms a film with excellent solvent resistance and physical strength. It is necessary to use good paint. This is because if the curability is poor, the colored coating may be peeled off or scraped off when the clear coating is applied, or the colored coating may migrate into the clear coating, resulting in a marked deterioration in the finished appearance.

The present inventors have discovered that a colored paint containing phenoxy resin as a main component has excellent curability, and does not peel off during clear coating.
We have already filed an application after discovering that it does not migrate into clear coatings (Japanese Patent Application No. 1-246202).

However, further research revealed that when the above-mentioned colored paint is cured by UV irradiation of the clear coating applied to the painted surface, the temperature rises and the bubbles in the porous substrate expand, causing the colored coating to may be washed up into the clear paint film, and if a large amount of clear paint is applied to the colored paint surface, and the reverse roll coater is not used after painting.
If the filling process is delayed due to such reasons, the colored coating may be scraped off.

The present invention aims to eliminate the various defects mentioned above in the method of coating porous materials with colored paints and ultraviolet-curable clear paints, and its characteristics are as follows: As a result, the object of the present invention was achieved.

That is, in the present invention, the number average molecular weight is 5.000 to 2.
0,000, and the weight average molecular weight is 10,000 to 10
0,000 phenoxy resin, urea resin, and acid catalyst as main components, and a step (I) of applying a colored paint (A) using an organic solvent containing a lower alcohol;
Step (II) of drying the colored coating film; Step (III) of coating the surface of the dried colored coating film with an ultraviolet curable clear paint (B) using a reverse roll coater or a knife coater.
) and a step (IV) of curing the clear coating film by irradiating it with ultraviolet rays.

The colored paint (A) used in the present invention is a liquid paint whose main components are a specified phenoxy resin, a urea resin, an acid catalyst, a coloring agent, and an organic solvent containing a lower alcohol.

The phenoxy resin can be produced mainly by the reaction of bisphenol A and epichlorohydrin, contains substantially no epoxy groups, and has a number average molecular weight (Mn) of 5.
,000-20,000, preferably 6,000-14
,000, weight average molecular weight (Mw) is 10,000~i
oo, ooo, preferably 20,000-50,000
must be included within the range. Furthermore, M
It is preferable that w/M n is in the range of 2 to 5, particularly 2.5 to 4.0, the hydroxyl value is in the range of 100 to 200, and the epoxy value is in the range of O to 10. Mn and/or M
If w is smaller than the above range, the drying properties of the colored coating film will be insufficient, so it will easily migrate into the coated film of the clear paint (B) that has been repeatedly applied (the finished appearance will be insufficient, and on the other hand, Mn
If and/or Mw is larger than the above range, it will be difficult to manufacture the coating material (A), so both are unfavorable and the object of the present invention cannot be achieved.

Among the commercially available phenoxy resins, for example, "Evokey 813J (Mitsui Toatsu Chemical Industry Co., Ltd.)"
product name), “Ebikuron H3O3”, “Ebikuron H
3O4J, ``Ebikron H305J, ``Ebikuro:/E
XA-1234 and “Evicron EXA-192J
(Both are product names manufactured by Dainippon Ink & Chemicals @),
and "Epicote #1o07J (trade name manufactured by Shell Chemical Co., Ltd.)".

The urea resin is preferably an alkyl etherified product of methylolated urea. Methylolated urea is obtained by adding 1 to 4 moles of formaldehyde per mole of urea,
This alkyl ether compound is obtained by reacting a monohydric alcohol having 1 to 5 carbon atoms.

The ratio of phenoxy resin to urea resin is based on the total solid weight of both resins: phenoxy resin 95-70%, especially 90-80%, urea resin 5-30%, especially 10-20%.
% is suitable.

Examples of acid catalysts include para-toluenesulfonic acid, hydrogen chloride, phosphoric acid, and trichloroacetic acid.
One or more selected from these may be used.

The amount of the acid catalyst to be added is preferably 4 to 10 parts by weight per 100 parts by weight of the total solid content of both resins.

The colored paint (A) can be obtained by dissolving or dispersing the above components in an organic solvent. It is necessary that the organic solvent contains a lower alcohol. The lower alcohol is preferably a monohydric alcohol having 1 to 2 carbon atoms, such as methanol or ethanol, and its content is determined according to the paint (
5 to 30% by weight of the total organic solvent A) is suitable. In addition, other organic solvents that can be used in combination with lower alcohols include:
Any material that dissolves the above phenoxy resin may be used, including alcohols such as propatool, butanol, and octatool, esters such as ethyl acetate, butyl acetate, and ethylene glycol monoethyl acetate, ethylene glycol monoethyl ether, and propylene glycol monoethyl. Examples include ethers such as ether, and ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and isophorone. Among these, ester-based, ketone-based and ether-based solvents are preferred, and hydrocarbon-based solvents such as toluene and xylene can also be used in combination with these solvents.

Furthermore, it is necessary to mix a coloring agent in the colored paint (A), and the coloring agent is for giving the porous material the desired color, and the coloring agent is a known coloring pigment that is usually mixed in general paints, Metallic pigments and dyes can be used.

In the colored paint (A), the urea resin is the curing agent component of the phenoxy resin, the acid catalyst is for promoting the crosslinking and curing reaction between the phenoxy resin and the curing agent component, and the lower alcohol is the curing agent component of the colored paint (A). Useful for maintaining storage stability.

The ultraviolet curable clear paint (B) is the colored paint (A).
) is a clear paint for forming a transparent film that is cured by ultraviolet irradiation and is applied to the painted surface of a polymerizable unsaturated resin,
It is a liquid paint whose main ingredients include a polymerizable unsaturated monomer and a photopolymerization initiator.

Polymerizable unsaturated resins have two or more polymerizable unsaturated bonds in one molecule, such as unsaturated polyester resins,
Examples include modified unsaturated polyester resins and unsaturated acrylic resins, and known ones can be used for all of these.

The unsaturated polyester resin is an esterified product of a polybasic acid containing a polymerizable unsaturated polybasic acid such as maleic acid (including anhydride) and fumaric acid, and a polyhydric alcohol.

The modified unsaturated polyester resin is made by adding a diisocyanate compound such as tolylene diisocyanate and a polymerizable vinyl monomer containing a water group such as hydroxyethyl acrylate to the above-mentioned unsaturated polyester resin or a saturated polyester resin that does not have a polymerizable unsaturated bond. ■ React with a polymerizable vinyl monomer containing a carboxyl group such as acrylic acid, ■ React with a polymerizable vinyl monomer containing a hydroxyl group or a glycidyl group (hydroxyethyl methacrylate, glycidyl acrylate, etc.) . ■Reacting polyhydric alcohols with allyl alcohol (including meta-allyl alcohol) or etherified products with benzyl alcohol (e.g., trimethylolpropane diallyl ether, trimethylolpropane monobenzyl ether, glycerin diallyl ether, etc.), etc. It has been modified by

The unsaturated acrylic resin is an acrylic resin containing a hydroxyl group and/or a carboxyl group and one selected from the above ■ to ■.
It can be obtained by further carrying out the reaction (2) above as needed to introduce a polymerizable unsaturated bond.

Regarding these polymerizable unsaturated resins, those whose main skeleton is polyester resin have a number average molecular weight of about 1.000 to 1.
0,000, those whose main skeleton is acrylic resin are about 1,
000 to 20,000, and the unsaturation equivalent is suitably in the range of 0.1 to 5. In addition, in the modified unsaturated polyester resin or unsaturated acrylic resin obtained based on the above (1), the content of the etherified substance is 5 to 3.
0 mol%, especially 10-20 mol% is preferred.

Next, the polymerizable unsaturated monomer is a compound having one or more polymerizable unsaturated bonds in one molecule. Specifically, esterified products of acrylic acid or methacrylic acid and monohydric alcohol having 1 to 20 carbon atoms, mono-, di- or Tri-esterified products, carboxyl group-containing unsaturated monomers such as acrylic acid or methacrylic acid, glycidyl group-containing unsaturated monomers such as glycidyl acrylate, amide unsaturated monomers such as acrylamide, and other unsaturated monomers such as styrene, vinyltoluene, and acrylonitrile. Examples include saturated monomers.

Examples of photopolymerization initiators include acetophenones, benzophenone, Michler's ketone, benzyl, benzoin,
Examples include benzoin ether, benzyl methyl ketal, and thione xanthates. Examples of the photosensitizer include n-butylamine, di-n-butylamine, triethylamine, toluethylenetetramine, allylthiourea, 4-dimethylaminoacetophenone, 4°4-bis(diethylamino)benzophenone, and S-benzyl-iso- Examples include thiuronium-p-toluenesulfinate, tri-n-butylphosphine, N-nitrosohydroxylamine derivatives, oxazoline compounds, and hexachloroethane.

The clear paint (B) used in the present invention has the above-mentioned components as main components, and the ratio of the polymerizable unsaturated resin to the polymerizable unsaturated monomer is 30% of the former based on the total weight of both components.
~70% by weight, and the latter is preferably in the range of 70 to 30% by weight, and furthermore, the photopolymerization initiator is in a total amount of 100% by weight of both the above components.
Parts by weight: 1 to 5 parts by weight are suitable.

In the clear paint (B) of the present invention, among the specific examples described above, it is preferable to use a paint whose coated surface undergoes no or almost no inhibition of curing by oxygen in the air when it is cured by ultraviolet irradiation. When applying paint (B) two or more times, it is recommended to use a clear paint that is susceptible to curing inhibition as the lower layer, and apply a paint that does not or hardly suffers from curing inhibition to the outermost layer in order to improve interlayer adhesion. preferred. Therefore, among the specific examples given above, clear paints that are susceptible to curing inhibition include those using polymerizable unsaturated resins such as unsaturated polyester resins and unsaturated acrylic resins; Alternatively, as a clear paint that is hardly susceptible to curing, a paint using a polyester resin modified with an ether compound or an unsaturated resin that is susceptible to curing inhibition mixed with a wax is preferable.

Waxes with a melting point of about 100°C or less are suitable, and specifically include vegetable waxes (e.g. carnauba, pyril wax), animal waxes (bees wax, shellac wax), and mineral waxes (montan wax). , ozotilite), petroleum-based (paraffin wax, microcrystalline wax), synthetic hydrocarbons (Fischer-Tropsch wax, low-molecular polyethylene), modified waxes (monokun derivatives, microwax derivatives), fatty acid esters and glycerides, hydrogenated waxes, amines, Examples include amides. The amount of waxes to be blended is preferably O.1 to 10 parts by weight per 100 parts by weight of the total amount of polymerizable unsaturated resin and polymerizable unsaturated monomer.

The coating film formed by the clear paint (B) used in the present invention is, in principle, colorless and transparent, but it is necessary to add colorants (coloring pigments,
There is no problem in adding dyes, metallic pigments, etc.).

The method of the present invention using the above-mentioned colored paint FA) and clear paint (B) will be explained.

Object to be coated: The method of the present invention is applied to a porous material that is flat and has a porous surface. This is because the characteristics of the porous coating material are fully utilized to fill the recesses of the colored coating surface with an ultraviolet curable clear coating to form a smooth rear coating.

Specific examples of objects to be coated include inorganic base materials such as wood gypsum board, cement board, asbestos slate board, calcium silicate board, and pulp cement board: ordinary plywood, special plywood,
Porous materials such as plywood such as chemically treated plywood and flooring; fiberboard such as fiberboard and particle board; porous plastics are preferred. These images of the object to be coated may be roughened and the surface thereof may be pretreated prior to coating with the colored paint (A).

Step (I) of applying the colored trowel (A) to the object to be coated: Adjust the coloring powder (A) to the object and apply by, for example, spray painting, roll coater painting, knife coat painting, brush painting, curtain flow coater painting, hand roller, etc. do. Among these, the roll coater may be either a natural type or a reverse type, and the roll material may include steel, rubber, sponge, and plastic. A knife coater or flow coater can also be applied. A suitable solid content during coating is 10 to 40% by weight.

In order to fill the inside of the porous part of the object with the colored paint (A), use one of the above methods and then use a reverse roll coater or knife coater while the paint film is still uncured. There is a way to pass it.

The coating amount of the colored paint (A) can be arbitrarily selected depending on the purpose and is not particularly limited, but approximately 5 to 300 g/m2 is suitable.

Step (II) of drying the colored paint film: Apply the colored paint (A) and dry it for 10 minutes at room temperature to 120°C.
When the coating is dried for about seconds to 30 minutes, most of the organic solvent in the coating is volatilized and the components mentioned above undergo a crosslinking reaction to form a hard coating. Drying methods include simply leaving it indoors, or forcing it to dry by heating it with hot air or far infrared rays.

Step (Ill) of applying an ultraviolet curable clear paint (B) to the colored coating surface using a reverse roll coater or knife coater: The clear paint (B) has a viscosity of 50 to 1.00 in advance.
It is preferable to adjust it to 0 centimeter voice (cps).

The coating material (B) is applied using a reverse roll coater or a knife coater. Specifically, (1) the paint (B) is applied with a natural roll coater or the like, and then passed through a reverse roll coater or knife coater to fill the paint (B) inside the pores of the surface to be coated. (11) After step (1) above, a clear paint is applied one or more times using an appropriate method.

The coating amount of the clear paint (B) can be arbitrarily selected as required, but it is preferably 25 to 300 g/m'' at each coating time.

In addition, when painting flooring materials that are required to have excellent abrasion resistance in accordance with (11) above, the clear paint (B) must contain wear-resistant aggregates (e.g. alumina, silicon carbide). etc.) are preferably blended in advance.

A reverse roll coater has a mechanism in which the rotation direction of the applicator roll is reverse to the direction of movement of the object to be coated. A knife coater allows paint (liquid) to pass under a knife onto the object being coated. These applicator rolls and knives are both applied to the surface to be coated with paint, and are scraped off while being stuffed into the pores. Therefore, when the clear paint (B) is applied with such a coating machine, the clear paint (B) is filled into the pores of the object to be coated.

Knife coaters include floating knives, inverted knives, in-line knives, knife-over-rolls, knife-over-blankets, and spanishing knives, all of which may be used in the present invention.

In order to paint the clear paint (B) while packing it into the pores of the workpiece using these coaters, apply the paint (B) to the workpiece in another direction (e.g., spray painting, natural roll coater painting, etc.). Clear paint (B) with brushing, etc.
It is preferable to apply the coating and then pass it through the coater.

Step of curing the clear coating film by irradiating ultraviolet rays (IV)
: Ultraviolet irradiation can be performed using, for example, a high-pressure mercury lamp (80 to 120 w/
cm), metal halide lamp (80-120 w/
cm), medium pressure mercury lamp, low pressure mercury lamp (chemical lamp)
This can be done using, for example.

Specifically, as described above (after applying the clear paint (B), the clear paint film can be quickly cured by passing it through an ultraviolet irradiation device. The irradiation time is 10 seconds to 5 minutes. degree is preferred.

After curing the clear paint film, add 1 coat of clear paint (B).
It is also possible to apply one coat or two or more coats.

A feature of the present invention is that when an ultraviolet curable clear paint is applied onto a colored surface using a reverse roll coater or a knife coater, the colored paint contains the phenoxy resin, urea resin, and acid catalyst as main components. This is where a paint is used. As a result, the following technical effects were obtained.

(1) Since the colored paint contains lower alcohol, it has excellent storage stability, and even if there is any leftover paint, it can be reused at a later date.

(2) When the colored paint is repeatedly damaged by the alcohol, etc., it forms a cured film that undergoes a three-dimensional crosslinking reaction, and has excellent physical strength and solvent resistance, so clear paint can be applied to the painted surface. CB) can be painted using the above method,
Furthermore, the colored coating film is not damaged and does not transfer to the clear coating film.

(3) Excellent adhesion between the colored paint film and the clear paint film.

(4) Since the colored coating film is cross-linked and cured, even if the clear coating (B) is applied to the painted surface and the temperature rises due to ultraviolet irradiation, the colored coating film will be damaged by the air bubbles contained in the coated object. I never get pushed down.

Next, examples and comparative examples of the present invention will be described.

Note that both parts and percentages are based on weight.

1. Production Example (1) Production of colored paint (A) The compositions and amounts (parts) shown in Table 1 were mixed and dispersed. Coating viscosity was 10-15 seconds/Ford Cup #4.

(*l) Dainippon Ink & Chemicals ■Product name: Phenoxy resin (Mn=12,000, Mw=40 000, Mw/
Mn=3.3) (*2) Mitsui Toatsu Chemical Industry ■Product name, phenoxy resin (
Mn=8.700, Mw=28,000, Mw/
M n = 3, 2) (*3) Product name manufactured by Dainippon Ink & Chemicals ■, butylated urea resin (*4) Part name manufactured by Mitsubishi Kasei ■ (*5), (*6) Product name manufactured by Fuji Shiki ■ ( *7) Kusumoto Kasei ■Product name, Pigment anti-settling agent (2) Manufacture of clear paint (B) Mixing based on the composition and amount (parts) shown in Table 2,
Manufactured in a dispersed manner.

Table 2 (*8) Product name, unsaturated acrylic resin manufactured by Arayo Kagaku Kogyo Co., Ltd.

(*9) Product name of Nippon Gosei Kagaku Co., Ltd., unsaturated polyester resin.

2. Examples Example 1 Sponge natural roll coater on oak veneer plywood
Then, apply (A-1) at a coating amount of 30 g/m2, then embed the colored paint into the conduit through a reverse roll coater, and then apply (A-1) at a coating amount of 10 g/7 m2 using a natural roll coater. After that (Step 1),
After drying for 30 seconds in a hot air drying oven adjusted to 100°C (Step II), (B-1) was applied to the coated surface using a natural coater at a coating amount of 15 g/m2, and then passed through a reverse roll coater. Then, (B-1) was further coated with a natural roll coater at a coating amount of 11 g/m'' (Step III).The clear coating film was then cured by irradiation with a high-pressure mercury lamp for 20 seconds.

Example 2 A birch veneer laminated plywood was coated with (A-2) at a coating amount of 25 g/m'' using airless auto spray (process step), and dried at 100°C for 30 seconds in a hot air drying oven (step II). Next, (B-2) was applied to the painted surface in the same manner as in (B-1) above (Step III), and after curing (Step IV),
The clear coating surface was polished with a wide belt sander, and then (B-3) was coated with a coating amount of 13 g/m'' using a natural coater and cured by irradiation with a high-pressure mercury lamp for 20 seconds.

Comparative Example 1 The same procedure as in Example 1 was conducted except that (A-1) in Example 1 was replaced with the colored paint (A-3) below.

(A-3) In (A-1), "200 parts of 45% Evicron H-303 solution" was added to "20% VAGH solution (trade name, vinyl chloride resin, manufactured by Union Carbide Co., Ltd.) 45 parts".
This is a colored paint in which "371 parts of xylene" was replaced with "121 parts of xylene".

Comparative Example 2 The same procedure as in Example 1 was conducted except that (A-1) in Example 1 was replaced with the colored paint (A-4) below.

(A-4) is the composition of (A-1) except that "60% Beckamine G-1850J" and "para-toluenesulfonic acid" are removed.

3. Performance test results Looking at the coated plates obtained in Examples 1 and 2, the finished appearance was good, and no phenomenon of the colored coating being pushed onto the clear coating was observed. Moreover, as a result of cross-cutting the painted surface and performing a peeling test using adhesive cellophane tape, all of these had excellent adhesion and no peeling occurred between the eyebrows.

On the other hand, in Comparative Example 1, a part of the colored coating film migrated into the clear coating film, and the reverse roll coater of the clear coating film
During the passage, the colored paint film was rubbed off, the finished appearance deteriorated, and furthermore, the glabella adhesion after the paint film was cured was insufficient, and peeling was observed between the clear paint film and the colored paint film. Comparative example 2
It was observed that when the clear coating film passed through the reverse roll coater, some of the colorant in the colored coating film was transferred to the reverse roll. The interlayer adhesion after coating was good.

Claims (1)

[Scope of Claims] The main components are a phenoxy resin, a urea resin, and an acid catalyst having a number average molecular weight of 5,000 to 20,000 and a weight average molecular weight of 10,000 to 100,000, and also contain a lower alcohol. The process of applying a colored paint (A) using an organic solvent (
I), Drying the colored coating film (II), Coating the ultraviolet curable clear paint (B) on the dry colored coating surface using a reverse roll coater or knife coater (I)
A painting finishing method comprising the steps of II) and curing the clear coating film by irradiating with ultraviolet rays (IV).